There is a need to produce high durability transparent windows and IR domes for airborne applications. These components must be resistant to thermal shock induced by aerodynamic heating and also to the long term effects of rain and solid particle erosion. A common material currently used in such applications is magnesium flouride, MgF.sub.2. Since it is too easily eroded and it does not adequately withstand temperature differentials, new optical materials made by cost effective fabrication processes are needed. Magnesium aluminate spinel is a possible replacement for magnesium flouride since spinel has a greater hardness that also results in greater erosion resistance. Production problems arise from the greater hardness of spinel since it is very difficult to machine, thus, producing a complex shape of spinel is both hard and expensive. Forging spinel crystals into complex shapes has not been heretofore possible. A technical note appearing in American Ceramic Society Bulletin, Vol. 56, No. 1 (1977) P. 1015-1017 entitled "Press Forged Al.sub.2 O.sub.3 -Rich Spinel Crystals for IR Application" by Paul F. Becker, describes a process whereby a single crystal spinel disk is deformed by slow compressive forces at high temperature into a thinner disk and achieves approximately 60% height reduction. This process is limited to simple planar shapes deformed by compressive stresses and resulting in a forged disk that has a certain number of precipitates which detract from the optical transmittance of the product.